Clinical Results After Clear Lens Extraction (CLE) and Bilateral Implantation of Extended-Range-of-Vision Presbyopia-Correcting Intraocular Lenses (IOL) in 30 Patients

Monofocal intraocular lenses (IOL) have been providing excellent distance vision in last few decades after cataract surgery [1]. Such patients still required spectacle correction for reading and intermediate distance, such as computer work. In the past decade, multifocal IOLs have been designed to improve spectacle independence after the cataract surgery [2]. At the same time, CLE has become increasingly accepted as an adequate alternative to other refractive procedures [3]. Controversial at first, CLE used to be reserved for patients with high myopia that could not be managed with laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) or even better for the patients with high hyperopia due to the fewer treatment modalities and the lesser risk of postoperative retinal detachment compared with highly myopic eyes. Along with the improvement of surgical techniques and technological advancements in IOL design and production, refractive lens exchange (RLE) increases its percentage in general number of all refractive procedures. A new promising design of IOL has recently been introduced, based on generation of extendedrange-of-vision resulting in satisfactory visual outcome while minimizing unwanted photic phenomena and visual disturbances [4,5]. TECNIS Symfony Intraocular lenses (IOL) implanted in this study uses echelettes, a type of diffraction grating, to extend the IOL’s focus range. At the same time, it corrects chromatic aberration to enhance contrast sensitivity [6]. The aim of this study was to evaluate the results after bilateral implantation of extended-rangeof-vision presbyopia-correcting lenses in terms of visual acuity at different distances, photic phenomena and subjective patient satisfaction with the visual outcome [7]. Research Article Medical & Surgical Ophthalmology Research C CRIMSON PUBLISHERS Wings to the Research


Introduction
Monofocal intraocular lenses (IOL) have been providing excellent distance vision in last few decades after cataract surgery [1]. Such patients still required spectacle correction for reading and intermediate distance, such as computer work. In the past decade, multifocal IOLs have been designed to improve spectacle independence after the cataract surgery [2]. At the same time, CLE has become increasingly accepted as an adequate alternative to other refractive procedures [3]. Controversial at first, CLE used to be reserved for patients with high myopia that could not be managed with laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) or even better for the patients with high hyperopia due to the fewer treatment modalities and the lesser risk of postoperative retinal detachment compared with highly myopic eyes.
Along with the improvement of surgical techniques and technological advancements in IOL design and production, refractive lens exchange (RLE) increases its percentage in general number of all refractive procedures. A new promising design of IOL has recently been introduced, based on generation of extendedrange-of-vision resulting in satisfactory visual outcome while minimizing unwanted photic phenomena and visual disturbances [4,5]. TECNIS Symfony Intraocular lenses (IOL) implanted in this study uses echelettes, a type of diffraction grating, to extend the IOL's focus range. At the same time, it corrects chromatic aberration to enhance contrast sensitivity [6]. The aim of this study was to evaluate the results after bilateral implantation of extended-rangeof-vision presbyopia-correcting lenses in terms of visual acuity at different distances, photic phenomena and subjective patient satisfaction with the visual outcome [7].

Study design and patient selection
This prospective case series study comprised 30 patients (60 eyes) of a mean age of 62+/-10. Patients selected in a study included moderately motivated individuals with adequate visual requirements and reasonable postoperative expectations. Twentytwo (44 eyes) patients had low to moderate hyperopia (between +1.00 D and +5.00 D), 4 (8 eyes) were highly hyperopic [more than+5.00 D] and 4 patients (8 eyes) had moderate to high myopia (in a range from -2.75 D to -7.00 D). Nine eyes with significant topographic astigmatism required implantation of toric IOL. Exclusion criteria were other eye conditions such as glaucoma, maculopathy, amblyopia, squint, abnormal binocular vision, visual field defects and abnormal preoperative parameters measured in preoperative assessment.

Surgical technique
All performed surgeries were done in a topical anesthesia by a standard sutureless phacoemulsification technique. Mydriasis was induced using tropicamide 1.0% and phenylephrinhydrochlorid 10.0%. A clear cornea microincision n of 2.2mm was located on a steep meridian. Surgical procedure was performed targeting mini-monovision on the non-dominant eye (-0.50 Dsph) and emmetropia on the dominant one that was operated one week after the first one [8,9]. The SRK-T formula was used in IOL power calculation for all eyes with axial length longer than 22.0mm. The Holladay I formula was used for all the other eyes [10]. All patients had bilateral implantation of extended-range-ofvision presbyopia-correcting IOL (Tecnis, Symfony) with the same surgical procedure and the same surgeon performing the surgery.

Outcome measurements
Postoperative distance, intermediate and near vision were measured 1, 3 and 6 months postoperatively.
Patients completed a questionnaire grading subjective satisfaction with the surgery outcome during the last follow-up visit [11]. How would you grade your overall satisfaction after the procedure on a scale 1-10?

Photic phenomena and patient satisfaction
In a survey given to the patients, slightly less than 10% of patients have reported some photic phenomena (halos, night glare and starbursts) with distribution shown in Figure 4.   These results correspond to results achieved in the multicentric Concerto study [12], showing UIVA results superior to the results achieved in numerous studies reporting intermediate visual acuity results with implanted bifocal and trifocal IOLs [13][14][15][16]. No significant difference was shown between visual acuities at all distances for 1 month, 3 months and 6 months follow-up visits.
Regarding stability, RLE probably represents the most stable refractive procedure, with +/-0.02 D per year reported over a 9-year follow-up period [17][18][19][20]. In terms of safety, opinions still differ, but RLE has passed a long way from an "idea before its time" to the "idea whose time has come" for an increasing number of ophthalmic surgeons, with care taken of the ethics and careful patient selection, detailed preoperative assessment, minutious surgical technique and adequate postoperative care. In terms of quality of vision, we were primarily interested in a subjective and objective parameters of vision quality of our patients after the implantation of Tecnis Symfony IOL to deliver the best possible care to our patients that were eager to reach the largest possible amount of spectacle independence. The achieved results were satisfactory for both our patients and we and consistent with previously reported results by other authors using the same or similar IOL [21].